Steel design and reliability using Eurocode 3

Steel design and reliability using Eurocode 3

Steel design and reliability using Eurocode 3

The twin aims of this research were to improve the presentation of codified design information and to investigate the methods used to calibrate the partial safety factors applied to resistance functions (yR factors) so as to improve both the economy and the reliability of the predictions.

A restructured version of EC3 (known as F-EC3) was developed by rearranging the design clauses on the basis of design tasks. This system enables the code to become more user-friendly. Hypertext versions of both EC3 and F-EC3 have been created on PC-based Microsoft Windows compatible software. The implications of hypertext on structural codes are investigated.

The procedure used for calibrating the yR-factors contained within EC3 (the Annex Z method) was reviewed and an alternative techniques involving less assumption proposed. A comprehensive set of measurements recording the material strength and the geometric properties of steel were obtained and collated. The large data set (over 7000 tests) was sufficient to evaluate the type of probability distribution characterising the variability of the basic material and geometric properties of structural steel. The resulting data were combined with experimental test results to determine the reliability of plate girder design and restrained beam design. The theoretical shear buckling resistance of plate girders (predicted by the simple post-critical and tension field methods) was compared with experimental test results to determine reliability. The analysis demonstrated that plate girder design falls well short of the target reliability and an adjustment to the design methods is required in order to ensure safe design. A series of 4-point bending tests on laterally restrained beams were conducted to establish the accuracy of the Mp1.Rd resistance function. This study quantifies the degree of conversation inherent in the Mp1.Rd design method and provides convincing evidence of the need to reduce the yR-factor applied to this resistance function. A modification is proposed to the design formulae which improves accuracy and permits the full moment capacity of restrained beams to be utilised.

Abstract

The twin aims of this research were to improve the presentation of codified design information and to investigate the methods used to calibrate the partial safety factors applied to resistance functions (yR factors) so as to improve both the economy and the reliability of the predictions.

A restructured version of EC3 (known as F-EC3) was developed by rearranging the design clauses on the basis of design tasks. This system enables the code to become more user-friendly. Hypertext versions of both EC3 and F-EC3 have been created on PC-based Microsoft Windows compatible software. The implications of hypertext on structural codes are investigated.

The procedure used for calibrating the yR-factors contained within EC3 (the Annex Z method) was reviewed and an alternative techniques involving less assumption proposed. A comprehensive set of measurements recording the material strength and the geometric properties of steel were obtained and collated. The large data set (over 7000 tests) was sufficient to evaluate the type of probability distribution characterising the variability of the basic material and geometric properties of structural steel. The resulting data were combined with experimental test results to determine the reliability of plate girder design and restrained beam design. The theoretical shear buckling resistance of plate girders (predicted by the simple post-critical and tension field methods) was compared with experimental test results to determine reliability. The analysis demonstrated that plate girder design falls well short of the target reliability and an adjustment to the design methods is required in order to ensure safe design. A series of 4-point bending tests on laterally restrained beams were conducted to establish the accuracy of the Mp1.Rd resistance function. This study quantifies the degree of conversation inherent in the Mp1.Rd design method and provides convincing evidence of the need to reduce the yR-factor applied to this resistance function. A modification is proposed to the design formulae which improves accuracy and permits the full moment capacity of restrained beams to be utilised.